Ability to stand alone and processing of open-class and closed-class words: Isolation versus context

Four experiments investigating processing of closed-class and open-class words in isolation and in sentence contexts are reported. Taft (1990) reported that closed-class words which could not meaningfully stand alone and open-class words which could not meaningfully stand alone incurred longer lexical decision responses than did control words. Taft also reported that closed-class and open-class words which could stand alone meaningfully were not associated with longer lexical decision responses than were control words. Experiments 1 and 2 replicated Taft 's effect of ability to stand alone on lexical decision responses to closed-class and open-class words presented in isolation. In Experiments 3 and 4, the same lexical decision targets were presented as part of semantically neutral context sentences in a moving window paradigm. The stand-alone effect was not present in Experiments 3 and 4. The results suggest Toft's conclusion that meaningfulness of a word influences lexical decision needs revision. An explanation is provided according to which support from message level and syntactic and lexical sources in sentence contexts influence words' perceived “meaningfulness.”     

Interactions between sentence context and word frequencyinevent-related brainpotentials

Event-related brain potentials (ERPs) were recorded as subjects silently read a set of unrelated sentences. The ERP responses elicited by open-class words were sorted according to word frequency and the ordinal position of the eliciting word within its sentence. We observed a strong inverse correlation between sentence position and the amplitude of the N400 component of the ERP. In addition, we found that less frequent words were associated with larger N400s than were more frequent words, but only if the eliciting words occurred early in their respective sentences. We take this interaction between sentence position and word frequency as evidence that frequency does not play a mandatory role in word recognition, but can be superseded by the contextual constraint provided by a sentence.     

Dual Processing of Open- and Closed-Class Words

A series of articles in the past two decades has suggested differential processing of open- and closed-class lexical items by normal adults. Difficulties in replicating a crucial study (Bradley, 1978), however, have weakened the dual route hypothesis. We matched 16 French open-class items to 16 closed-class items for phonological structure, word length, and relative word frequency. Three agrammatic aphasics were asked to read each word in isolation and in a sentence context. Error analysis revealed strikingly more phonological errors on closed-class than open-class items. Dysfluencies were greater on closed-class items and contributed to greater overall reading time for the closed-class words, consistent with a two-route model for the production of closed- and open-class lexical items in Broca's aphasics and, thus, normals.     

Event-related brain potentials to grammatical errors and semantic anomalies

Event-related brain potentials (ERPs) were recorded while subjects silently read several prose passages, presented one word at a time. Semantic anomalies and various grammatical errors had been inserted unpredictably at different serial positions within some of the sentences. The semantically inappropriate words elicited a large N400 component in the ERP, whereas the grammatical errors were associated with smaller and less consistent components that had scalp distributions different from that of the N400. This result adds to the evidence that the N400 wave is more closely related to semantic than to grammatical processing. Additional analyses revealed that different ERP configurations were elicited by open-class (“content”) and closed-class (“function”) words in these prose passages.     

Grammatical incongruency and vocabulary types

Four experiments conducted in French were performed to investigate the role of grammatical congruency and vocabulary class on lexical decision times. In Experiment 1, using a double lexical decision, slower reaction times were found for pairs of words that disagreed in gender or number than for congruent pairs. Experiments 2, 3, and 4 tested this effect with a standard priming procedure. The grammatical congruency effect varied according to presentation times (130, 150, or 500 msec) and to vocabulary class of context word (closed or open). Closed-class context words induced stronger grammatical effect than did open-class words. These results suggest that the grammatical link existing between the two words of a pair is more immediately computed when the first one is a closed-class item and argue for a distinct computational role of open- and closed-class words in sentence processing.     

Grammatical class effects in relation to normal and aphasic sentence processing

Agrammatic, Broca's aphasic patients, Wernicke's aphasic patients, and neurologically intact control subjects were asked to detect target letters in prose passages and in a scrambled word passage. The targets were embedded, in some instances, in content words (open-class vocabulary items), and in other instances, in function words (closed-class vocabulary items). With respect to the prose passages, both the control subjects and Wernicke's aphasic patients were more apt to notice target letters when they appeared in the open-class items than when in closed-class items; by contrast, the agrammatic Broca's patients showed no vocabulary class detection difference. The Wernicke's patients were not entirely normal, however: Whereas the normal subjects showed a much smaller vocabulary class effect for letter detection in the scrambled condition, the Wernicke's maintained the pattern they had shown in the prose condition. These and other findings obtained on the letter cancellation task are discussed in relation to lexical access mechanisms geared to sentence parsing.     

Differences in the perception and time course of syntactic and semantic violations

A reading time and an ERP experiment conducted in Italian investigated the parser's responses to a syntactic violation (subject-verb number agreement) and to a semantic violation (subject-verb selectional restriction), examining the time course of comprehension processes until sentence end. The reading-time data showed that the syntactic violation was detected earlier than the semantic one and that the two violations differed in the time-course. The ERP data fully supported the reading time data: Syntactic anomalies elicited a left anterior negativity (LAN) and a P600. Semantic anomalies elicited a N400 centred on the parietal sites which started 90 ms later (latency 430 ms) than the LAN. Furthermore, the N400 evoked by the words that followed the target word continued and increased until sentence end. The results are discussed with respect to the hypotheses that the parser constructs distinct syntactic and semantic analyses of a sentence and that this characteristic holds cross-linguistically. The appropriateness of different methodologies to the study of sentence processing is also evaluated.     

On the Brain Response to Syntactic Anomalies: Manipulations of Word Position and Word Class Reveal Individual Differences

In two experiments, event-related brain potentials (ERPs) were recorded from 13 scalp locations while subjects read sentences containing a syntactically or a semantically anomalous word. The position (sentence-embedded vs sentence-final) and word class (open vs closed) of the syntactic anomalies were manipulated. In both experiments, semantically anomalous words elicited an enhanced N400 component. Syntactically anomalous closed class words elicited a widely distributed late positive wave (P600) regardless of the word's position and a smaller negative-going effect that was largest over anterior sites when the anomaly occurred in sentence-final position. The response to syntactically anomalous open class words revealed striking qualitative individual differences: These words elicited a P600 response in the majority of subjects and an N400 response in others. The proportion of subjects exhibiting the N400 response was greater when the anomaly occurred in sentence-final position. These results are interpreted in the context of prior findings, and implications for the hypothesis that syntactic and semantic anomalies elicit distinct brain potentials are discussed.     

Spoken word recognition in context: evidence from Chinese ERP analyses

Two event-related potential (ERP) experiments were conducted to investigate spoken word recognition in Chinese and the effect of contextual constraints on this process. In Experiment 1, three kinds of incongruous words were formed by altering the first, second or both syllables of the congruous disyllabic terminal words in high constraint spoken sentences. Results showed an increase of N400 amplitude in all three incongruous word conditions and a delayed N400 effect in the cohort incongruous condition as compared with the rhyme incongruous and plain incongruous condition. In addition, unlike results in English, we found that the N400 effect in the rhyme incongruous condition disappeared earlier than in the plain incongruous condition. In Experiment 2, three kinds of nonwords derived from sentence congruous words were constructed by altering few or many phonetic features of the onset or the whole of the first syllable, and the resulting nonwords appeared as disyllabic terminal forms in either high or low constraint sentences. All three nonword conditions elicited the N400 component. In addition, in high constraint sentences but not in low, the amplitude and duration of the N400 varied as a function of the degree of phonetic mismatch between the terminal nonword and the expected congruous word.     

世界知识在句子理解中的整合时程

Hagoort等(2004)应用背离范式发现世界知识和单词意义在句末的整合是同时进行的。本研究将背离信息提前到句首短语中,旨在探讨世界知识在句子阅读过程中被整合的时程特征。实验采用四词句子为材料,其中第二个词（目标词）含有单词意义或世界知识背离信息,记录并比较被试在阅读后三个词时诱发的脑电变化。结果发现：与正确句子比较,无论是单词意义背离还是世界知识背离,背离目标词均引发出经典的N400,二者在峰值时间和始潜时上无显著差异,但世界知识背离信息诱发的N400波幅值相对较小。句中的后继单词不再诱发类似的N400;但到句子结尾,两类含有背离信息句子的句末正常单词又诱发出类似N400的一个负波。结果提示,在句子理解过程中,世界知识的整合与单词意义的整合相似,可能是随着句子理解过程即时进行的,整合的结果不影响后继信息的加工;但到了句末,读者在对整个句子内容作真实性判断时会对先前进行过的整合再进行考察。     

Word category and verb--argument structure information in the dynamics of parsing

One of the core issues in psycholinguistic research concerns the relationship between word category information and verb-argument structure (e.g. transitivity) information of verbs in the process of sentence parsing. In two experiments (visual versus auditory presentation) using event-related brain potentials (ERPs), we addressed this question by presenting sentences in which the critical word simultaneously realized both a word category and a transitivity violation. ERPs for sentences with both types of violation clustered with the patterns for sentences with a word category violation only, but were different from the patterns elicited by argument structure violations in isolation, since only the latter elicited an N400 ERP component. The finding that an argument structure violation evoked an N400 only if the phrase structure of the respective sentence was correct suggests that a successful integration of the word category information of a verb functionally precedes the application of its argument structure information.     

Closed-class words as first syllables do interfere with lexical decisions for nonwords: implications for theories of agrammatism

It has been proposed that a principal cause of the agrammatism of some Broca's aphasics is that such patients, unlike normal subjects, are unable to make use of a special retrieval mechanism for closed-class ("function") words (D. C. Bradley, 1978, Computational distinctions of vocabulary type, Unpublished Ph.D. thesis; D. C. Bradley, M. F. Garrett, & E. B. Zurif, 1980. In D. Caplan (Ed.), Biological studies of mental processes). The main evidence for the existence of such a mechanism consisted of two observations: (1) the recognition of open-class words was observed to be frequency-sensitive, but that of closed-class words was not; and (2) lexical decisions for nonwords which began with open-class words were delayed, whereas there was no such interference for nonwords which began with closed-class words. However, the first of these observations has proved nonreplicable (e.g., B. Gordon & A. Caramazza, 1982, Brain and Language, 15, 143-160, 1983, Brain and Language, 19, 335-345; J. Segui, J. Mehler, W. Frauenfelder, & J. Morton, 1982, Neuropsychologia, 20, 615-627), and in the present paper, three lexical decision experiments are reported in which it is found that, when certain confounding variables are controlled, nonwords which begin with closed-class words are subject to interference. Moreover, contrary to a suggestion of Kolk and Blomert (1985, Brain and Language, 26, 94-105) the interference is independent of the presence of closed-class items in the lexical decision word list. It seems, then, that closed-class words are not qualitatively different from open-class words with respect either to frequency sensitivity or to nonword interference, and in consequence, the above proposed explanation of agrammatism is left without major empirical support.     

Closed- and open-class lexical access in agrammatic and fluent aphasics

Bradley, Garrett, and Zurif (Bradley, Computational distinctions of vocabulary type. Unpublished doctoral dissertation, MIT Press; Cambridge, MA, 1978; Biological studies of mental processes, MIT Press, Cambridge, MA, 1980) have suggested that closed-class word access is normally mediated by a different route than the open-class one, and that the loss of this closed-class route might account for agrammatism. However, in an earlier study ( Gordon & Caramazza, Brain and Language, 15, 143–160, 1982) we were not able to confirm a meaningful difference between closed- and open-class word frequency responsiveness of the type Bradley (unpublished dissertation, 1978) had seemed to find in normal subjects. We have now done a direct comparison of closed-class frequency sensitivity in agrammatic and nonagrammatic aphasics, to directly test Bradley and colleagues' hypotheses and to avoid some of the experimental problems with between-class frequency comparisons. We find that closed-class words behave similarly whether or not the subject is agrammatic. Therefore, the differences between agrammatic and nonagrammatic aphasics must arise at a deeper level (or levels) of lexical processing than the one probed by the frequency sensitivity effect.     

Gestural development and its relation to a child's early vocabulary

Gesture and language are tightly connected during the development of a child's communication skills. Gestures mostly precede and define the way of language development; even opposite direction has been found. Few recent studies have focused on the relationship between specific gestures and specific word categories, emphasising that the onset of one gesture type predicts the onset of certain word categories or of the earliest word combinations.The aim of this study was to analyse predicative roles of different gesture types on the onset of first word categories in a child's early expressive vocabulary. Our data show that different types of gestures predict different types of word production. Object gestures predict open-class words from the age of 13 months, and gestural routines predict closed-class words and social terms from 8 months. Receptive vocabulary has a strong mediating role for all linguistically defined categories (open- and closed-class words) but not for social terms, which are the largest word category in a child's early expressive vocabulary. Accordingly, main contribution of this study is to define the impact of different gesture types on early expressive vocabulary and to determine the role of receptive vocabulary in gesture-expressive vocabulary relation in the Croatian language.     

Making sense of sentences in schizophrenia: electrophysiological evidence for abnormal interactions between semantic and syntactic processing

Event-related potentials to critical verbs were measured as patients with schizophrenia and healthy controls read sentences word by word. Relative to their preceding context, critical verbs were (a) congruous, (b) incongruous and semantically unrelated to individual preceding words (pragmatic-semantic violations), (c) incongruous but semantically related to individual preceding words (animacy-semantic violations), or (d) syntactically anomalous. The N400 was modulated normally in patients, suggesting that semantic integration between individual words within sentences was normal in schizophrenia. The amplitude of the P600 to both syntactic and animacy-semantic violations was reduced in patients relative to controls. The authors suggest that, in schizophrenia, an abnormality in combining semantic and syntactic information online to build up propositional meaning leaves sentence processing to be primarily driven by semantic relationships between individual words.     

N400 and P600 or the role of the ERP correlates in sentence comprehension: some applications to the Italian language

In the present study, event-related brain potentials (ERPs) were applied to the study of language comprehension in the Italian language. The ERPs were recorded from 10 electrodes while the participants read (Experiment 1) or listened (Experiment 2) to sentences containing semantic or syntactic anomalies. Final words that were inconsistent with the sentence context elicited a negative wave at about 400 ms poststimulus that was more concentrated in the posterior sites of the scalp, whereas final words that were incongruous with the grammatical structure (subject-verb nonagreement) elicited a positive wave at about 600 ms poststimulus that was homogeneously distributed on the scalp. The authors found no differences based on the perceptual modality of the stimulus (visual or auditory), nor did they find different ERP correlates as a function of task relevance (explicit-implicit task induction). The available evidence indicated that the ERP response to semantic anomalies was at least partially distinct from the ERP response to syntactic anomalies, and that a syntactic parser is a plausible process included in sentence comprehension. The two semantic and syntactic effects appear as automatic processes of the decoding of the anomalies and also modality-independent processes. Cross-linguistic applications are considered in the general discussion.     

N400 and P600 or the Role of the ERP Correlates in Sentence Comprehension: Some Applications to the Italian Language

In the present study, event-related brain potentials (ERPs) were applied to the study of language comprehension in the Italian language. The ERPs were recorded from 10 electrodes while the participants read (Experiment 1) or listened (Experiment 2) to sentences containing semantic or syntactic anomalies. Final words that were inconsistent with the sentence context elicited a negative wave at about 400 ms poststimulus that was more concentrated in the posterior sites of the scalp, whereas final words that were incongruous with the grammatical structure (subject-verb nonagreement) elicited a positive wave at about 600 ms poststimulus that was homogeneously distributed on the scalp. The authors found no differences based on the perceptual modality of the stimulus (visual or auditory), nor did they find different ERP correlates as a function of task relevance (explicit-implicit task induction). The available evidence indicated that the ERP response to semantic anomalies was at least partially distinct from the ERP response to syntactic anomalies, and that a syntactic parser is a plausible process included in sentence comprehension. The two semantic and syntactic effects appear as automatic processes of the decoding of the anomalies and also modality-independent processes. Cross-linguistic applications are considered in the general discussion.     

A comparison of sentence- and discourse-level semantic processing: an ERP study

Eighteen subjects listened to sentences ending with semantically congruent or incongruent words. Each congruent sentence was embedded at the end of a short story so that the final word was semantically acceptable at the sentence level but incongruent in terms of discourse context. The same stories were also presented with congruent endings. Auditory ERPs elicited by the final words in these sentences and stories were compared. Both sentence- and discourse-level semantic integration were associated with N400 and Late Positive Component (LPC) effects in addition to a new component, P550. Local and global semantic processing, although evoking the same components, were characterized by differential effects on ERP amplitudes according to the amount of text integrated and its congruence. These results indicate similar cognitive processes of context build up, underlying sentence- and discourse-semantic processing.     

Zipf's Law in transcribed speech

Summary Based on large samples of written text. Zipf:s Law holds that the logarithms of frequencies of words, and the number of different words at those frequencies, have an inverse linear relationship. This study tested this law on an oral sample by analysis of a transcribed interview which had been conducted for an unrelated study. A second purpose was to test whether the law holds differently for open- vs closed-class words. The words in the interview were tabulated by frequencies and numbers of words at each frequency, and separated by syntactic class. As Zipf found for written samples, the law provides a reasonable summary of the data for the less frequently used words but predicts fewer different words among the most frequently used words than were actually found. Linear regressions performed for each syntactic class revealed that the regression equation for open-class words provided the best fit to Zipf's law. The sample of closed-class words, containing a much smaller proportion of low frequency words, revealed a poor fit to Zipf's law.The author wishes to thank Diane Beyerchen, Wendy Calla, Edward Kulick, and Clinton B' Walker for their cooperation and suggestions.     

The activation of word class information during speech production

In 5 picture-word interference experiments the activation of word class information was investigated. The first experiment, in which subjects used bare nouns to describe the pictures, failed to reveal any interference effect of noun distractor words as opposed to closed-class distractor words. In the next 4 experiments the pictures were named by using a definite determiner and the noun completing a sentence fragment. The data demonstrate that noun distractors interfere more strongly with picture naming than do non-noun distractors. This held for both visual and auditory presentation of the distractor words. The interference effect showed up in a time window where semantic interference can usually be observed, supporting the assumption that at an early stage of lexical access semantic and syntactic activation processes overlap.